Equine proliferative enteropathy: a cause of weight loss, colic, diarrhoea and hypoproteinaemia in foals on three breeding farms in Canada.

Proliferative enteropathy (PE) is a transmissible enteric disease caused by Lawsonia intracellularis. An outbreak of equine PE was diagnosed in foals from 3 breeding farms. Most foals had been weaned prior to the appearance of clinical signs, which included depression, rapid and marked weight loss, subcutaneous oedema, diarrhoea and colic. Poor body condition with a rough haircoat and a potbellied appearance were common findings in affected foals. Respiratory tract infection, dermatitis and intestinal parasitism were also found in some foals. Haematological and plasma biochemical abnormalities included hypoproteinaemia, transient leucocytosis, anaemia and increased serum creatinine kinase concentration. Postmortem diagnosis of PE was confirmed on 4 foals based on the presence of characteristic intracellular bacteria within the apical cytoplasm of proliferating crypt epithelial cells of the intestinal mucosa, using silver stains, and by results of PCR analysis and immunohistochemistry. Antemortem diagnosis of equine PE was based on the clinical signs, hypoproteinaemia and the exclusion of common enteric infections. Faecal PCR analysis was positive for the presence of L. intracellularis in 6 of 18 foals tested while the serum of all 7 foals with PE serologically evaluated had antibodies against L. intracellularis. Most foals were treated with erythromycin estolate alone or combined with rifampin for a minimum of 21 days. Additional symptomatic treatments were administered when indicated. All but one foal treated with erythromycin survived the infection. This study indicates that equine PE should be included in the differential diagnosis of outbreaks of rapid weight loss, diarrhoea, colic and hypoproteinaemia in weanling foals.

Persistence of porcine reproductive and respiratory syndrome virus infection in a swine operation.

A herd of Quebec seedstock pigs experienced in early 1992 a typical outbreak of porcine reproductive and respiratory syndrome (PRRS) associated with lesions of interstitial, proliferative and necrotizing pneumonia in weaned piglets. The nature of the infection was confirmed by serology using indirect immunofluorescence (IIF) and virus isolation in primary cultures of porcine alveolar macrophages (PAM). Farm production recovered after eight weeks of losses. In order to evaluate the persistence of infection in the herd, five SPF-piglets were introduced in two different sections of the PRRS-affected barn four months after the disappearance of clinical symptoms, and two others were placed in a neighboring building with apparently healthy farrow-to-finnish pigs. Clinical signs, body temperature, humoral immune response, virological and histopathological findings were recorded over a 42-day period. Clinical signs were evident in all of the sentinels and prolonged fever (> or = 40 degrees C) was recorded one day post-exposure (PE). Antibody titers to PRRS virus could be detected by IIF on PAM seven days PE, and reached 1:1024 by day 21 PE. Three of the sentinels developed significant virus neutralizing antibody titers (> 1:8 to < or = 1:128) by day 35 PE. In all cases, the virus could be isolated from the serum between day 7 and 42 PE. Thus, the virus and specific antibodies coexisted for several weeks. Lesions of interstitial pneumonia was demonstrated in few animals. In experimental inoculation studies, the viral strain isolated from the sentinel pigs produced severe reproductive disorders in two sows inoculated at 95 days of gestation.(ABSTRACT TRUNCATED AT 250 WORDS)

Hemorrhagic myelomalacia following general anesthesia in a horse.

An 18-month-old male Belgian horse was anesthetized and placed in dorsal recumbency for cryptorchidectomy. Xylazine was used for sedation and guaifenesin with thiamylal for induction of anesthesia. A surgical plane of anesthesia was maintained with halothane. During anesthesia, second-degree atrio-ventricular blocks, hypoventilation and a 1-minute duration rise of mean arterial pressure (80 to 130 mm Hg) occurred. Total anesthesia time was 1 hour. On recovery from anesthesia, the horse exhibited flaccid paralysis of the hind limbs and was only able to elevate himself to a dog sitting position. The horse was humanely euthanized 22 hours postoperatively due to a lack of improvement in clinical signs. Hemorrhagic poliomyelomalacic lesions of the spinal cord were observed on histopathological examination of the spinal cord.

Swine reproductive and respiratory syndrome in Québec: Isolation of an enveloped virus serologically-related to Lelystad virus.

Sera were collected from convalescent sows and sick piglets from six pig farms in southern Quebec that have experienced outbreaks of the so-called porcine reproductive and respiratory syndrome. By indirect immunoperoxidase, a few of these sera (4 of 14) (28.6%) were found to be positive for antibody to the Lelystad virus, whereas by indirect immunofluorescence 30 of 36 (83.3%) were positive for antibody to the antigenically-related American isolate ATCC-VR2332. Pregnant sows inoculated intranasally with filtered homogenates prepared from the lungs of necropsied piglets obtained from a seropositive farm developed fever, inappetence, and reproductive failure characterized by stillbirths and various stages of mummification. Lesions of interstitial pneumonia were induced in experimentally-infected specific pathogen-free piglets. A virus, having morphological and biological characteristics of viruses assigned to the family Togaviridae, was isolated from lung tissues of experimentally-infected animals; it could only be propagated in primary cultures of porcine alveolar macrophages. Identification of the virus was confirmed by indirect immunofluorescence using a monoclonal antibody directed against the nucleocapsid protein of the ATCC-VR2332 isolate and porcine sera that were found positive for antibody to both the Lelystad and ATCC-VR2332 isolates.

Antigenic variant of swine influenza virus causing proliferative and necrotizing pneumonia in pigs.

A new antigenic variant of swine influenza virus was isolated from the lungs of pigs experiencing respiratory problems in 7 different swine herds in Quebec. Pigs of different ages were affected, and the main clinical signs were fever, dyspnea, and abdominal respiration. Coughing was not a constant finding of the syndrome. At necropsy, macroscopic lesions included the overall appearance of pale animals, general lymphadenopathy, hepatic congestion, and consolidation of the lungs. Histopathologic findings were mainly proliferative pneumonia with a significant macrophage invasion, necrotic inflammatory cells in the alveoli and the airways, a marked proliferation of type II pneumocytes, and thickening of the alveolar septae. Fluorescent antibody examination of lungs of sick piglets did not demonstrate porcine parvovirus, transmissible gastroenteritis virus, or encephalomyocarditis virus. However, evidence of the presence of an influenza type A infection was demonstrated by indirect immunofluorescence (IIF) staining using monoclonal antibody directed to nucleocapsid protein (NP) of human type A influenza virus. The virus was isolated either by intra-allantoic inoculation of specific-pathogen-free embryonating hens' eggs or propagation in canine kidney (MDCK) cells in the presence of trypsin. By hemagglutination inhibition tests, no cross-reactivity was demonstrated with human influenza H1N1, H2N2, and H3N2 strains, and infected MDCK cells did not react by IIF with monoclonal antibodies to NP protein of type B influenza virus. The hemagglutination activity of plaque-purified isolates was only partly inhibited by hyperimmune serum produced to subtypes A/Wisconsin/76/H1N1 and A/New Jersey/76/H1N1 of swine influenza virus. Gnotobiotic piglets that were infected intranasally with egg-adapted isolates of this new antigenic variant of swine influenza virus developed the very same type of lesions observed in field cases.

Outbreaks in Quebec pig farms of respiratory and reproductive problems associated with encephalomyocarditis virus.

Encephalomyocarditis virus (EMCV) was isolated from tissues of aborted fetuses and weaned and suckling piglets from 4 different pig farms in Quebec. The farms were experiencing reproductive failure in sows of different parities concomitant to respiratory problems in suckling and postweaning piglets. At necropsy, gross lesions were confined to the lung and consisted of pulmonary congestion and edema of various degrees. Lesions of multifocal interstitial to proliferative pneumonia were found in the lungs of these piglets. Bacteriologic examination of various tissues from necropsied pigs yielded no pathogens in most cases. No significant antibody titers against 3 swine viruses (transmissible gastroenteritis virus, porcine parvovirus, and swine influenza virus) and two bovine viruses (bovine viral diarrhea and infectious bovine rhinotracheitis viruses) were detected in the sera of convalescent pigs. The Quebec EMCV isolates were antigenically related to the reference ATCC-VR129 strain of EMCV, as demonstrated by indirect immunofluorescence, serum neutralization (SN), and Western immunoblotting. However, one of the Quebec isolates could be distinguish by SN. EMCV-specific SN antibody titers up to 1:12,800 were detected in thoracic and ascitis fluids of aborted fetuses and in sera of convalescent pigs. A possible pneumotropic EMCV variant in swine may exist.

Torsion of abdominal organs in sows: a report of 36 cases.

Necropsy records of 36 sows with torsion of abdominal organs involving individually the stomach, the spleen, a liver lobe or the intestine were reviewed for the years 1970 to 1983, and the age, the clinical signs and the gross lesions were recorded. These acute abdominal accidents were characterized clinically by sudden death. Dry sows from large breeding units were affected. Twenty-six cases were diagnosed between January 1981 and December 1983 while only ten cases had been seen between 1970 and 1980. Gastric torsion was the most common condition (40% of the cases) and the other three conditions were equally represented (20% each). Management practises that could be responsible for the apparent increase in occurrence of this problem are discussed.